Skelly: Really the laboratory work in this case came first. But to me, the cart was before the horse because we really didn’t understand the natural history of reproductive deformities in many groups.Į360: When did people first notice that there was something weird going on with these frogs? There had been some laboratory work that did in fact use pollutants and figure out whether exposure through pollutants like pesticides might cause these kinds of deformities. I started off trying to understand where sexual deformities in amphibians came from in the environment. When I started on this project I really didn’t know whether I was going to be studying pollution or what. Tell us how that happened.ĭavid Skelly: Well, as an ecologist, I start with the animals. Yale Environment 360: You came to the question of pollution not as a medical researcher but as a wildlife biologist - you studied frogs.

“The fact that these kinds of estrogens out in the environment can have this kind of effect on a vertebrate - many people would say that that alone is a basis for us to be concerned,” says Skelly. One thing seems clear: The deformities showing up in frogs are almost certainly not caused by a single chemical, but rather by a whole suite of substances - including medicines excreted by humans into the environment - that act in concert to mimic hormones like estrogen or cause other ill effects. In an interview with Yale Environment 360 contributing writer Carl Zimmer, Skelly described what chemicals may be causing these abnormalities in frog populations, and explained why this phenomena may have troubling implications not only for amphibians, but for other vertebrates, including humans.

Frog mutating flat worm